snapshot: sagernet/gvisor v0.0.0-20250811.0-sing-box-mod.1

Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом
без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в
каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для
неё не нужна.

Module path github.com/sagernet/gvisor сохранён намеренно: на него
опирается replace-директива суперпроекта.

Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show
и переносилась на новый пин копированием.

SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH

pkg/tcpip/stack/packet_buffer_list.go

@@ -0,0 +1,87 @@
+// Copyright 2022 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at //
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stack
+
+// PacketBufferList is a slice-backed list. All operations are O(1) unless
+// otherwise noted.
+//
+// Note: this is intentionally backed by a slice, not an intrusive list. We've
+// switched PacketBufferList back-and-forth between intrusive list and
+// slice-backed implementations, and the latter has proven to be preferable:
+//
+//   - Intrusive lists are a refcounting nightmare, as modifying the list
+//     sometimes-but-not-always modifies the list for others.
+//   - The slice-backed implementation has been benchmarked and is slightly more
+//     performant.
+//
+// +stateify savable
+type PacketBufferList struct {
+	pbs []*PacketBuffer
+}
+
+// AsSlice returns a slice containing the packets in the list.
+//
+//go:nosplit
+func (pl *PacketBufferList) AsSlice() []*PacketBuffer {
+	return pl.pbs
+}
+
+// Reset decrements all elements and resets the list to the empty state.
+//
+//go:nosplit
+func (pl *PacketBufferList) Reset() {
+	for i, pb := range pl.pbs {
+		pb.DecRef()
+		pl.pbs[i] = nil
+	}
+	pl.pbs = pl.pbs[:0]
+}
+
+// Len returns the number of elements in the list.
+//
+//go:nosplit
+func (pl *PacketBufferList) Len() int {
+	return len(pl.pbs)
+}
+
+// PushBack inserts the PacketBuffer at the back of the list.
+//
+//go:nosplit
+func (pl *PacketBufferList) PushBack(pb *PacketBuffer) {
+	pl.pbs = append(pl.pbs, pb)
+}
+
+// PopFront removes the first element in the list if it exists and returns it.
+//
+//go:nosplit
+func (pl *PacketBufferList) PopFront() *PacketBuffer {
+	if len(pl.pbs) == 0 {
+		return nil
+	}
+	pkt := pl.pbs[0]
+	pl.pbs = pl.pbs[1:]
+	return pkt
+}
+
+// DecRef decreases the reference count on each PacketBuffer
+// stored in the list.
+//
+// NOTE: runs in O(n) time.
+//
+//go:nosplit
+func (pl PacketBufferList) DecRef() {
+	for _, pb := range pl.pbs {
+		pb.DecRef()
+	}
+}